Answer:
A. Generator
Step-by-step explanation:
An alternator which is also called a generator basically converts mechanical energy into electric energy.
An alternator is used in a vehicle to charge the battery. It supplies electric power to the automobile.It is attached to the engine and is driven by a belt system . When the alternator does not charge the battery, it can be understood that it is not working as it no longer recharges the battery, though the engine of the automobile runs.